Moisture control is an important consideration in designing athletic apparel. A person exercising produces sweat, and evaporation of the sweat keeps body temperature at an appropriate level. This process helps the person to stay cool in the summer and warm in the winter. However, if a person's athletic apparel absorbs the perspiration, it becomes wet and can hinder the evaporation process which is important to temperature control. Wet fabric sticks to the skin and can cause the wearer to become cold in cooler weather.
Many fabrics used in athletic apparel, such as cottons, nylons and polyesters, have this problem with absorbing moisture. To solve this problem, fabrics can be treated with a wicking finish. A wicking finish is a coating applied to the fabric which allows it to wick moisture away from the inside of the fabric, from next to the skin to the outside of the fabric, where the moisture can evaporate. Because the wet layer is not next to the skin after the moisture has been wicked away, the wearer is more comfortable and less likely to become cold. However, a fabric with a wicking finish may lose its wicking properties after repeated washing. Also, such finishes interfere with the dyeing process.